Communication apparatus

ABSTRACT

A communication apparatus for correcting a situation of a spectrum inverted signal includes a channel estimation module and an equalization module. The channel estimation module determines a channel estimation parameter, and receives at least one frame signal to generate a convolution restored frame signal corresponding to the frame signal. The equalization module includes a first computation circuit and a second computation circuit. The first computation circuit receives the channel estimation parameter and the convolution restored frame signal to generate a transformation channel estimation parameter and a transformed convolution restored frame signal. The second computation circuit receives the transformed channel estimation parameter and the transformed convolution restored frame signal to generate an original frame signal corresponding to the frame signal. The first computation circuit further feeds back a transient original frame signal to the channel estimation module to update the channel estimation parameter.

This application claims the benefit of Taiwan application Serial No.105114253, filed May 9, 2016, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates in general to a communication apparatus, and moreparticularly to a communication apparatus capable of processing spectruminverted signals.

Description of the Related Art

In a communication system, on a transmission path from a transmitter toa receiver, a transmission signal encounters shielding effects ofvarious obstacles on the path in a way that a reception error rate ofthe receiver is increased. In the above situation, in knowntechnologies, a communication apparatus is provided at the receiver toperform compensation on the transmission signal to lower thetransmission error rate. However, when the transmission signal thecommunication apparatus receives is a spectrum inverted signal, theestimation on the transmission channel of the transmission signal cannotbe accurately conducted, subsequently leading to an inaccurate estimatedresult and an inoperable compensation operation.

Therefore, there is a need for a communication apparatus capable ofprocessing spectrum inverted signals.

SUMMARY OF THE INVENTION

It is a primary object of the present invention to provide acommunication apparatus capable of processing spectrum inverted signalsto improve issues of the prior art.

The present invention discloses a communication apparatus for correctinga situation of a spectrum inverted signal. The communication apparatusincludes: a channel estimation module, determining a channel estimationparameter, receiving at least one frame signal to generate a convolutionrestored frame signal, wherein the channel estimation parameter, theframe signal and the convolution restored frame signal are time-domainsignals; and an equalization module, coupled to the channel estimationmodule, including a first computation circuit that receives the channelestimation parameter and the convolution restored frame signal togenerate a transformed channel estimation parameter and a transformedconvolution restored frame signal, wherein the transformed channelestimation parameter and the transformed convolution restored framesignal are frequency-domain signals, and a second computation circuitthat is coupled to the first computation circuit and receives thetransformed channel estimation parameter and the transformed convolutionrestored frame signal to generate an original frame signal correspondingto the frame signal, wherein the original frame signal is a time-domainsignal. The first computation circuit further feeds back a transientoriginal frame signal to the channel estimation module to update thechannel estimation parameter.

The present invention further discloses a method for correcting asituation of a spectrum inverted signal that a communication apparatusreceives. The communication apparatus includes a channel estimationmodule and an equalization module. The method includes: determining achannel estimation parameter; receiving at least one frame signal by thechannel estimation module to generate a convolution restored framesignal corresponding to the frame signal, wherein the channel estimationparameter, the frame signal and the convolution restored frame signalare time-domain signals; receiving the channel estimation parameter andthe convolution restored frame signal by a first computation circuit ofthe equalization module to generate a transformed channel estimationparameter and a transformed convolution restored frame signal, whereinthe transformed channel estimation parameter and the transformedconvolution restored frame signal are frequency-domain signals; andreceiving the transformed channel estimation parameter and thetransformed convolution restored frame signal by a second computationcircuit of the equalization module to generate an original frame signalcorresponding to the frame signal, wherein the original frame signal isa time-domain signal. The first computation circuit further feeds back atransient original frame signal to the channel estimation module toupdate the channel estimation parameter.

The above and other aspects of the invention will become betterunderstood with regard to the following detailed description of thepreferred but non-limiting embodiments. The following description ismade with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an analog-to-digital converting deviceaccording to an embodiment of the present invention;

FIG. 2A is a detailed block diagram of a first computation circuitaccording to the embodiment in FIG. 1;

FIG. 2B is a detailed block diagram of a second computation circuitaccording to the embodiment in FIG. 1;

FIG. 3A is another detailed block diagram of the first computationcircuit according to the embodiment in FIG. 1;

FIG. 3B is a detailed block diagram of another the second computationcircuit according to the embodiment in FIG. 1;

FIG. 4 is a flowchart of a correction process according to an embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a block diagram of a communication apparatus 1 according toan embodiment of the present invention. As shown in FIG. 1, thecommunication apparatus 1, suitable for a Digital Terrestrial MultimediaBroadcast (DTMB) standard, includes a channel estimation module 10 andan equalization module 12, and may be disposed at a receiver of acommunication system (not shown). When the receiver receives a framesignal, the communication apparatus 1 may be used to correct a situationof a spectrum inverted signal. Meanwhile, the communication apparatus 1is capable of accurately estimating a transmission channel including aspectrum inverted signal to provide a better compensation effect forsubsequent frame signals. The communication apparatus 1 of theembodiment is also suitable for a frame signal including a normalspectrum signal. Preferably, the frame signal transmitted according tothe DTMB standard includes a plurality of frame header signals and aplurality of frame body signals. Wherein, each frame header signal is apseudo noise (PN) sequence coded and includes 420, 595 or 945 symbols;each frame body signal is a Bose Chaudhuri Hocquenghem coded andlow-density parity check (LDPC) coded, and includes 3780 symbols.

The operation of the communication apparatus 1 may be divided into twoworking cycles. In the first working cycle, the channel estimationmodule 10 determines a channel estimation parameter. When a frame signalthe channel estimation module 10 receives is a frame header signal, theequalization module 12 returns a transient original frame signal of aprevious frame (i.e., a conjugate signal corresponding to the originalframe signal) to the channel estimation module 10 to adaptively updatethe previously determined channel estimation parameter. In a secondworking cycle following the first working cycle, when the frame signalthe channel estimation module 10 receives is a frame body signal,another original frame signal, to be used in the next first workingcycle, is correspondingly generated from the frame body signal throughthe operations of the channel estimation module 10 and the equalizationmodule 12. As such, the estimation operation is repeatedly performed onthe frame signals in the two alternating working cycles, hence not onlycorrecting frame signals containing spectrum inverted signals but alsogenerating more accurate frames signals for the communication system touse.

Operation details of the channel estimation module 10 and theequalization module 12 are described below, again with reference toFIG. 1. In the embodiment, the channel estimation module 12 determines achannel estimation parameter −jh*(t), where j=√{square root over ( )}−1,and * represents a complex conjugate. The channel estimation module 10further receives at least one frame signal r(t), and performs aconvolution restoration operation on a frame body signal to generate aconvolution restored frame signal y*(t) corresponding to the framesignal r(t). The frame signal r(t) in this embodiment may furtherinclude a frame header signal. For simplicity, both of the frame headersignal and the frame body signal are represented by the frame signalr(t) in this embodiment. In the embodiment below, the signals usedinclude time-domain signals x(t) and frequency-domain signals x(f),where x represents different types of signals, t represents the time andf represents the frequency. Further, the convolution restorationoperation in this embodiment refers to a sequence of input signals(including frame body signals and frame header signals) and a channelimpulse response, and performs a circular convolution calculation basedon the two to obtain another output sequence corresponding to the inputsignals. Details of the calculation and formulae actually conducted arenot the main spirit of the present invention, and shall not be furtherdiscussed.

After the communication apparatus 1 receives the frame signal r(t), thechannel estimation module 10 performs a channel estimation operation tooutput the channel estimation parameter −jh*(t), and further performs aconvolution restoration operation to output the convolution restoredframe signal y*(t). The first computation circuit 120 then performs afast Fourier transform (FFT) operation to output a transformedconvolution restored frame signal, a transformed channel estimationparameter and a transformed equalized frame signal. Next, the secondcomputation circuit 122 performs another conjugate operation and areal-imaginary permutation operation. In the above situation, regardlessof whether the frame signal r(t) includes a spectrum inverted signal,the equalization signal 12 is capable of generating an original framesignal s(t) corresponding to the frame signal r(t). Further, thetransformed equalized frame signal S(f) obtained in this embodiment maybe transmitted to a signal-to-noise ratio (SNR) estimation module of thecommunication apparatus 1 to estimate the SNR corresponding to thecurrent frame signal r(t), and the estimated SNR is provided to thecommunication system for subsequent operations—such is encompassedwithin the scope of the present invention.

FIG. 2A shows a detailed block diagram of a first computation circuit 20in the embodiment in FIG. 1. As shown in FIG. 2A, the first computationcircuit 20 includes FFT circuits 200_1 and 200_2, a division circuit202, a grouping circuit 204 and an inverse fast Fourier transform (IFFT)circuit 206. The FFT circuits 200_1 and 200_2, coupled to the channelestimation module 10, receives the convolution restored frame signaly*(t) and the channel estimation parameter −jh*(t), and generates atransformed convolution restored frame signal Y*(−f) signal and atransformed channel estimation parameter −jH*(−f) through an FFToperation. As the frame signals include spectrum inverted signals, therepresentations of the transformed convolution restored frame signalY*(−f) signal and the transformed channel estimation parameter −jH*(−f)after the FFT operation represent frequency inverted signals. Thedivision circuit 202, coupled to the FFT circuits 200_1 and 200_2,receives the transformed convolution restored frame signal Y*(−f) signaland the transformed channel estimation parameter −jH*(−f), and dividesthe transformed convolution restored frame signal Y*(−f) signal by thetransformed channel estimation parameter −jH*(−f) to generate atransformed equalized frame signal jZ*(−f), which also represents afrequency inverted signal. The grouping circuit 204, coupled to thedivision circuit 202, receives the transformed equalized frame signaljZ*(−f), and performs a hard decision to output a transformed originalframe signal jS*(−f). Meanwhile, the grouping circuit 204 may determinewhether the transformed equalized frame signal jZ*(−f) is a spectruminverted signal, and at the same time correspondingly determines whetherthe transformed equalized frame signal jZ*(−f) is a system informationcarrier or a data carrier according to a sequence parametercorresponding to the transformed equalized frame signal jZ*(−f) tofurther output a determination signal S_D (i.e., correspondinglydetermining whether the transformed equalized frame signal jZ*(−f) is aspectrum inverted signal) and the transformed original frame signaljS*(−f). The mechanism for detecting a spectrum inverted signal isgenerally known to one person skilled in the art, and shall be omittedherein. For example, the sequence parameter of the transformed equalizedframe signal jZ*(−f) may be 0, 1, 2, . . . , 3778, 3779. When thegrouping circuit 204 determines that the transformed equalized framesignal jZ*(−f) is a spectrum inverted signal, the grouping circuit 204further refers to the sequence parameter of the transformed equalizedframe signal jZ*(−f) to determine the pattern of a carrier. Morespecifically, when the sequence parameter of the transformed equalizedframe signal jZ*(−f) falls in 0 to 18 and 3763 to 3779, the transformedequalized frame signal jZ*(−f) is determined as a system informationcarrier, and a hard decision is then performed on each systeminformation carrier by a decision circuit (not shown) corresponding tothe system information carrier to obtain symbol signals that thetransmitter transmits. For example, when the system information carrieruses τ/2-binary phase shift keying (BPSK) for transmission, a τ/2-BPSKdecision circuit is correspondingly used. When the sequence parameter ofthe transformed equalized frame signal jZ*(−f) falls in 19 to 3762, thetransformed equalized frame signal jZ*(−f) is determined as a datacarrier, and a hard decision is performed on each data carrier byanother decision circuit corresponding to the data carrier to obtainsymbol signals that the transmitter transmits. For example, when thedata carrier uses 16 quadrature amplitude modulation (16QAM) fortransmission, a 16QAM decision circuit is correspondingly used. Further,when the grouping circuit 204 has determined that the transformedequalized frame signal jZ*(−f) is a normal spectrum signal, the groupingcircuit 204 further refers to the parameter sequence of the transformedequalized frame signal jZ*(−f) to determine the pattern of the carrier.More specifically, when the sequence parameter of the transformedequalized frame signal jZ*(−f) falls between 0 and 17 and 3762 and 3779,the transformed equalized frame signal jZ*(−f) is determined as a systeminformation carrier. When the sequence parameter of the transformedequalized frame signal jZ*(−f) falls between 18 and 3761, thetransformed equalized frame signal jZ*(−f) is determined as a datacarrier. It should be noted that, the method for setting the sequenceparameter in this embodiment is an example for illustration purposes andis not to be construed as limitations to the present invention. The IFFTcircuit 206, coupled to the grouping circuit 204, receives thetransformed original frame signal jS*(−f) to perform an IFFT operationto correspondingly generate a transient original frame signal js*(t),and at the same time feeds back the transient original frame signaljs(*t) to the channel estimation module 10 to update the channelestimation parameter −jh*(t).

FIG. 2B shows a detailed block diagram of a second computation circuit22 in the embodiment in FIG. 1. As shown in FIG. 2B, the secondcomputation circuit 22 includes a first calculation circuit 220, asecond calculation circuit 222, a third calculation circuit 224 and afourth calculation circuit 226. The first calculation circuit 220includes a first buffer 2200 and a conjugate calculation circuit 2022.The first buffer 2200 receives the transformed convolution restoredframe signal Y*(−f). The conjugate calculation circuit 2202, coupled tothe first buffer 2200, transforms the transformed convolution restoredframe signal Y*(−f) to a calculated frame signal Y(f) (may correspond tothe originally received frame signal r(t)). The second calculationcircuit 222 includes a second buffer 2220 and a first permutationcalculation circuit 2222. The second buffer 2220 receives thetransformed channel estimation parameter −jH*(−f). The first permutationcalculation circuit 2222, coupled to the second buffer 2220, transformsthe transformed channel estimation parameter −jH*(−f) to a calculatedchannel estimation parameter H(f). The third calculation circuit 224includes a third buffer 2240 and a second permutation calculationcircuit 2242. The third buffer 2240 receives the transformed equalizedframe signal jZ*(−f). The second permutation calculation circuit 2242,coupled to the third buffer 2240, transforms the transformed equalizedframe signal jZ*(−f) to a calculated equalized frame signal Z(f). Thefourth calculation circuit 226 includes a fourth buffer 2260 and a thirdpermutation calculation circuit 2262. The fourth buffer 2260 receivesthe transformed original frame signal jS*(−f). The third permutationcalculation circuit 2262, coupled to the fourth buffer 2260, transformsthe transformed original frame signal jS*(−f) to the original framesignal S(f). As such, the second computation circuit 22 may obtain theoriginal frame signal S(f), and output the original frame signal S(f),the calculated frame signal Y(f), and the calculated channel estimationparameter H(f) to an SNR estimation module of the communicationapparatus 1 for an SNR operation. Further, the calculated equalizedframe signal Z(f) is transmitted to a BCH/LDPC decoder of thecommunication apparatus 1 for associated operations.

In the embodiment, the first buffer 2200, the second buffer 2220, thethird buffer 2240 and the fourth buffer 2260 further receive thedetermination signal S_D, so as to determine to output the transformedconvolution restored frame signal Y*(−f), the transformed channelestimation parameter −jH*(−f), the transformed equalized frame signaljZ*(−f) and the transformed original frame signal jS*(−f) according to afirst-in-first-out (FIFO) sequence or a last-in-first-out (LIFO)sequence. For example, in the embodiment, the first buffer 2200, thesecond buffer 2220, the third buffer 2240 and the fourth buffer 2260 aresequentially written with the transformed convolution restored framesignal Y*(−f) having a sequence parameter 0, 1, 2, . . . , 3778 and3779, the transformed channel estimation parameter −jH*(−f), thetransformed equalized frame signal jZ*(−f) and the transformed originalframe signal jS*(−f). Further, when the grouping circuit 204 determinesthat the original frame signal jS*(−f) is a spectrum inverted signal,the first buffer 2200, the second buffer 2220, the third buffer 2240 andthe fourth buffer 2260 sequentially output the transformed convolutionrestored frame signal Y*(−f) having a sequence parameter 0, 1, 2, . . ., 3778 and 3779, the transformed channel estimation parameter −jH*(−f),the transformed equalized frame signal jZ*(−f) and the transformedoriginal frame signal jS*(−f), and respectively transmit the foursignals to the conjugate calculation circuit 2202, the first permutationcalculation circuit 2222, the second permutation calculation circuit2242 and the third permutation calculation circuit 2262 for associatedoperations.

Further, the conjugate calculation circuit 2202 performs a conjugateoperation. More specifically, the conjugate calculation circuit 2202divides the transformed convolution restored frame signal Y*(−f) to areal signal and an imaginary signal, adds a negative sign to theimaginary signal to form a new imaginary signal, and outputs theoriginal real signal and the new imaginary signal to form the calculatedframe signal Y(f). The first permutation calculation circuit 2222performs a real-imaginary permutation operation. More specifically, thefirst permutation calculation circuit 2222 divides the transformedchannel estimation parameter −jH*(−f) to a real signal and an imaginarysignal, changes the original real signal to a new imaginary signal andthe original imaginary signal to a new real signal, and multiplies thenew imaginary signal and the new imaginary signal by a negative sign toform the calculated channel estimation parameter H(f). The secondpermutation calculation circuit 2422 and the third permutationcalculation circuit 2262 also perform another real-imaginary permutationoperation. However, differences of the second permutation calculationcircuit 2422 and the third permutation calculation circuit 2262 arethat, the equalized frame signal jZ*(−f) or the transformed equalizedframe signal jS*(−f) is divided into a real signal and an imaginarysignal, the original real signal is changed to a new imaginary signaland the original imaginary signal to a new real signal, and the new realsignal and the new imaginary signal are outputted to form the calculatedequalized frame signal Z(f) or the original frame signal S(f).

FIG. 3A shows a detailed block diagram of another first computationcircuit 30 in the embodiment in FIG. 1A. As shown in FIG. 3A, similar tothe first computation circuit 20 in FIG. 2A, the first computationcircuit 30 in this embodiment also includes FFT circuits 300_1 and300_2, a division circuit 302, a grouping circuit 304 and an IFFTcircuit 306, which have similar coupling relationships and operations.The grouping circuit 304 further determines whether the convolutionrestored frame signal y*(t) includes a spectrum inverted signal, andmeanwhile performs a hard decision. Accordingly, before the groupingcircuit 304 completes its determination, the FFT circuits 300_1 and300_2 first output a transformed channel estimation parameter −jH*(f)and a transformed convolution restored frame signal Y*(f) according to aFIFO sequence. When the grouping circuit 304 determines that theconvolution restored frame signal y*(t) includes a spectrum invertedsignal, the FFT circuits 300_1 and 300_2 then output a transformedchannel estimation parameter −jH*(f) and a transformed convolutionrestored frame signal Y*(t) according to a LIFO sequence. For example,assume that the sequence parameter of the transformed convolutionrestored frame signal Y*(f) is 0, 1, 2, . . . , 3778 ad 3779. When thegrouping circuit 204 determines that the transformed convolutionrestored frame signal Y*(f) includes a spectrum inverted signal, the FFTcircuits 300_1 and 300_2 correspondingly output the transformedconvolution restored frame signal Y*(f) having the sequence parameter 0,3779, 3778, . . . , 2 and 1. When the grouping circuit 304 determinesthat the convolution restored frame signal y*(t) includes a normalspectrum signal, the FFT units 300_1 and 300_2 correspondingly outputthe transformed convolution restored frame signal Y*(f) having thesequence parameter 0, 1, 2, . . . , 3778 and 3779. Meanwhile, in thisembodiment, the transformed channel estimation parameter −jH*(f) and thetransformed convolution restored frame signal Y*(f) representnon-spectrum inverted signals. Further, after receiving the transformedconvolution restored frame signal Y*(f) and the transformed channelestimation parameter −jH*(f), the division circuit 302 divides thetransformed convolution restored frame signal Y*(f) by the transformedchannel estimation parameter −jH*(f) to generate a transformed equalizedframe signal jZ*(f), which also represents a non-spectrum invertedsignal. Further, when the FFT circuits 300_1 and 300_2 determine thatthe convolution restored frame signal y*(t) includes a spectrum invertedsignal and the output the transformed convolution restored frame signalY*(f) having the sequence parameter 0, 3779, 3778, . . . , 2 and 1, theIFFT circuit 306 correspondingly receives the transformed original framesignal jS*(f) having the sequence parameter 0, 3779, 3778, . . . , 2 and1, correspondingly generates the transient original frame signal js*(t),and feeds the transient original frame signal js*(t) back to the channelestimation module 10 to update the channel estimation parameter −jh*(t).

FIG. 3B shows a detailed block diagram of another second computationcircuit 32 in the embodiment in FIG. 1. As shown in FIG. 3B, similar tothe first computation circuit 22 in FIG. 2B, a second computationcircuit 32 in this embodiment includes a first calculation circuit 320,a second calculation circuit 322, a third calculation circuit 324 and afourth calculation circuit 326. One difference of the second computationcircuit 32 is that, none of the first calculation circuit 320, thesecond calculation circuit 322, the third calculation circuit 324 and afourth calculation circuit 326 includes a buffer; that is, the firstcalculation circuit 320 includes a conjugate calculation circuit 3202,the second calculation circuit 322 includes a first permutationcalculation circuit 3220, the third calculation circuit 324 includes asecond permutation calculation circuit 3240, and the fourth calculationcircuit 326 includes a third permutation calculation circuit 3260.Accordingly, the conjugate calculation circuit 3202 performs a conjugateoperation to transform the transformed convolution restored frame signalY*(f) to a signal Y(f) (may correspond to the originally received framesignal r(t)). The first permutation calculation circuit 3220 performs areal-imaginary permutation operation to transform the transformedchannel estimation parameter −jH*(f) to a signal H(f). The secondpermutation calculation circuit 3240 and the third permutationcalculation circuit 3260 perform another real-imaginary permutationoperation to respectively transform the transformed equalized framesignal jZ*(f) and the transformed original frame signal jS*(f) to thesignal Z(f) and the original frame signal S(f). As such, the secondcomputation circuit 32 in this embodiment may also obtain the originalframe signal S(f), and output the original frame signal S(f) and thesignals Y(f) and H(f) to an SNR estimation module to perform an SNRestimation operation. Further, the signal Z(f) is transmitted to aBCH/LDPC decoder of the communication apparatus 1 for associatedoperations. Further, details of the conjugate operation of the conjugatecalculation circuit 3200, and the real-imaginary permutation operationsof the first permutation calculation circuit 3220, the secondpermutation calculation circuit 3240 and the third permutationcalculation circuit 3260 are similar to the operations associated withthe conjugate calculation circuit 2202, the first permutationcalculation circuit 2222, the second permutation calculation circuit2242 and the third permutation calculation circuit 2262, and shall beomitted herein.

The correction method suitable for the communication apparatus 1 of theembodiment may be concluded to a correction process 40, and is codedinto a program code that is stored in a storage device of thecommunication system and executed by a processor module of thecommunication system. As shown in FIG. 4, the correction process 40includes following steps.

In step 400, the correction process 40 begins.

In step 402, the channel estimation module 10 determines a channelestimation parameter.

In step 404, the channel estimation module 10 receives at least oneframe signal to generate a convolution restored frame signalcorresponding to a frame signal.

In step 406, the first computation circuit 120 of the equalizationmodule 12 receives the channel estimation parameter and the convolutionrestored frame signal to generate a transformed channel estimationparameter and a transformed convolution restored frame signal.

In step 408, the second computation circuit 122 of the equalizationmodule 12 receives the transformed channel estimation parameter and thetransformed convolution restored frame signal to generate an originalframe signal corresponding to the frame signal.

In step 410, the correction process 40 ends.

In simple, after performing the operation mechanism from step 400 tostep 410 of the correction process 40, associated operations of oneworking cycle is complete. Further, through the control of a processormodule or a user, the number of times of performing the correctionprocess 40 may be determined according to the number of frame signalsthat the communication apparatus 1 receives. However, such is not to beconstrued as a limitation to the present invention. Details of thecorrection process 40 may be referred from the description associatedwith FIG. 1 to FIG. 3, and shall be omitted herein.

It should be noted that, operations of multiple computation circuits arerespectively integrated in the first computation circuit and the secondcomputation circuit in the teaching of the embodiments. However, oneperson skilled in the art may adaptively encode step 406 and step 408into a plurality of sub-codes that are stored in the storage device(s)of the first computation circuit and/or the second computation circuit.Further, the communication system may further include a plurality ofprocessor units for executing the plurality of sub-codes, which may beexecuted in a multiplexed manner with the coordination of the pluralityof calculation circuits in the first computation circuit and the secondcomputation circuit, hence significantly enhancing processingperformance and accuracy of the communication system. It should be notedthat, such modification is also encompassed within the scope of thepresent invention. Further, in practice, one person skilled in the artcan understand that the channel estimation module, the equalizationmodule and the SNR estimation module may be realized by digitalcircuits, and are not to be construed as limitations to the presentinvention.

While the invention has been described by way of example and in terms ofthe preferred embodiments, it is to be understood that the invention isnot limited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

What is claimed is:
 1. A communication apparatus, correcting a situationof an spectrum inverted signal that the communication apparatusreceives, comprising: a channel estimation module, determining a channelestimation parameter, receiving at least one frame signal to generate aconvolution restored frame signal corresponding to the frame signal,wherein the channel estimation parameter, the frame signal and theconvolution restored frame signal are time-domain signals; and anequalization module, coupled to the channel estimation module,comprising: a first computation circuit, receiving the channelestimation parameter and the convolution restored frame signal togenerate a transformed channel estimation parameter and a transformedconvolution restored frame signal, wherein the transformed channelestimation parameter and the transformed convolution restored framesignal are frequency-domain signals; and a second computation circuit,coupled to the first computation circuit, receiving the transformedchannel estimation parameter and the transformed convolution restoredframe signal to generate an original frame signal corresponding to theframe signal, wherein the original frame signal is a time-domain signal;wherein, the first computation circuit further feeds back a transientoriginal frame signal to the channel estimation module to update thechannel estimation parameter, and the transient original frame signal isa time-domain signal.
 2. The communication apparatus according to claim1, wherein the first computation circuit comprises: a plurality of fastFourier transform (FFT) circuits, coupled to the channel estimationmodule, receiving the channel estimation parameter and the convolutionrestored frame signal to generate the transformed channel estimationparameter and the transformed convolution restored frame signal, whereinboth of the transformed channel estimation parameter and the transformedconvolution restored frame signal represent a frequency inverted signal;a division circuit, coupled to the plurality of FFT circuits, receivingthe transformed convolution restored frame signal and the transformedchannel estimation parameter to generate a transformed equalized framesignal, wherein the transformed equalized frame signal represents afrequency inverted signal and is a frequency-domain signal; a groupingcircuit, coupled to the division circuit, receiving the transformedequalized frame signal, determining whether the transformed equalizedframe signal is the spectrum inverted signal, and correspondinglyoutputting a determination signal and a transformed original framesignal according to a sequence parameter; and an inverse fast Fouriertransform (IFFT) circuit, coupled to the grouping circuit, receiving thetransformed original frame signal to generate the transient originalframe signal, and feeding back the transient original frame signal tothe channel estimation module to update the channel estimationparameter.
 3. The communication apparatus according to claim 2, whereinthe second computation circuit comprises: a first calculation circuit,comprising a first buffer and a conjugate calculation circuit, the firstbuffer receiving the transformed convolution restored frame signal, theconjugate calculation circuit transforming the transformed convolutionrestored frame signal to a calculated frame signal; a second calculationcircuit, comprising a second buffer and a first permutation calculationcircuit, the second buffer receiving the transformed channel estimationparameter, the first permutation calculation circuit transforming thetransformed channel estimation parameter to a calculated channelestimation parameter; a third calculation circuit, comprising a thirdbuffer and a second permutation calculation circuit, the third bufferreceiving the transformed equalized frame signal, the second permutationcalculation circuit transforming the transformed equalized frame signalto a calculated equalized frame signal; and a fourth calculationcircuit, comprising a fourth buffer and a third permutation calculationcircuit, the fourth buffer receiving the transformed original framesignal, the third permutation calculation circuit transforming thetransformed original frame signal to the original frame signal.
 4. Thecommunication apparatus according to claim 3, wherein the first buffer,the second buffer, the third buffer and the fourth buffer furtherreceive the determination signal, and output the transformed convolutionrestored frame signal, the transformed channel estimation parameter, thetransformed equalized frame signal and the transformed original framesignal according to a first-in-first-out (FIFO) or sequence or alast-in-first-out (LIFO) sequence.
 5. The communication apparatusaccording to claim 1, wherein the first calculation circuit comprises: aplurality of fast Fourier transform (FFT) circuits, coupled to thechannel estimation module, receiving the channel estimation parameterand the convolution restored frame signal to generate the transformedchannel estimation parameter and the transformed convolution restoredframe signal, wherein both of the transformed channel estimationparameter and the transformed convolution restored frame signalrepresent a non-spectrum inverted signal; a division circuit, coupled tothe plurality of FFT circuits, receiving the transformed channelestimation parameter and the transformed convolution restored framesignal to generate a transformed equalized frame signal, wherein thetransformed equalized frame signal represents a non-spectrum invertedsignal; a grouping circuit, coupled to the division circuit, receivingthe transformed equalized frame signal, determining whether thetransformed equalized frame signal is the spectrum inverted signal, andcorrespondingly generating a transformed original frame signal; and aninverse fast Fourier transform (IFFT) circuit, coupled to the groupingcircuit, receiving the transformed original frame signal to generate thetransient original frame signal, and feeding back the transient originalframe signal to the channel estimation module to update the channelestimation parameter.
 6. The communication apparatus according to claim5, wherein the FFT circuits further refer to a determination resultindicating whether the transformed equalized frame signal is thespectrum inverted signal to further determine to output the transformedchannel estimation parameter and the transformed convolution restoredframe signal according to a first-in-first-out (FIFO) sequence or alast-in-first-out (LIFO) sequence.
 7. The communication apparatusaccording to claim 5, wherein the second computation circuit comprises:a first calculation circuit, comprising a conjugate calculation circuit,transforming the transformed convolution restored frame signal to acalculated frame signal; a second calculation circuit, comprising afirst permutation calculation circuit, transforming the transformedchannel estimation parameter to a calculated channel estimationparameter; a third calculation circuit, comprising a second permutationcalculation circuit, transforming the transformed equalized frame signalto a calculated equalized frame signal; and a fourth calculationcircuit, comprising a third permutation calculation circuit,transforming the transformed original frame signal to the original framesignal.
 8. The communication apparatus according to claim 1, wherein theframe signal is correspondingly a frame header signal or a frame bodysignal; in a first working cycle, when the frame signal that the channelestimation module receives is the header frame signal, the frame headersignal is processed by the channel estimation module and theequalization module to correspondingly obtain the original frame signal,the equalization module feeds back the original frame signal to thechannel estimation module to update the channel estimation parameter; ina second working cycle following the first working cycle, when the framesignal that the channel estimation module receives is the frame bodysignal, the frame body signal is processed by the channel estimationmodule and the equalization module to correspondingly obtain theoriginal frame signal and is used for correcting the situation of thespectrum inverted signal received that the communication apparatusreceives.
 9. A correction method, for correcting a situation of aninverted signal received that a communication apparatus receives, thecommunication apparatus comprising a channel estimation module and anequalization module, the correction method comprises: determining achannel estimation parameter; receiving at least one frame signal by thechannel estimation module to generate a convolution restored framesignal corresponding to the frame signal, wherein the channel estimationparameter, the frame signal and the convolution restored frame signalare time-domain signals; receiving the channel estimation parameter andthe convolution restored frame signal by a first computation circuit ofthe equalization module to generate a transformed channel estimationparameter and a transformed convolution restored frame signal, whereinthe transformed channel estimation parameter and the convolutionrestored frame signal are frequency-domain signals; receiving thetransformed channel estimation parameter and the transformed convolutionrestored frame signal by a second computation circuit of theequalization module to generate an original frame signal correspondingto the frame signal, wherein the original frame signal is a time-domainsignal; wherein, the first computation circuit further feeds back atransient original frame signal to the channel estimation module toupdate the channel estimation parameter, and the transient originalframe signal is a time-domain signal.
 10. The communication methodaccording to claim 9, wherein the step of receiving the channelestimation parameter and the convolution restored frame signal by thefirst computation circuit of the equalization module to generate thetransformed channel estimation parameter and the transformed convolutionrestored frame signal further comprises: receiving the channelestimation parameter and the convolution restored frame signal by aplurality of fast Fourier transform (FFT) circuits to generate thetransformed channel estimation parameter and the transformed convolutionrestored frame signal, wherein both of the transformed channelestimation parameter and the transformed convolution restored framesignal represent a frequency inverted signal; receiving the transformedchannel estimation parameter and the transformed convolution restoredframe signal by a division circuit to generate a transformed equalizedframe signal, wherein the transformed equalized frame signal representsa spectrum inverted signal and is a frequency-domain signal; receivingthe transformed equalized frame signal by a grouping circuit,determining whether the transformed equalized frame signal is thespectrum inverted signal, and correspondingly outputting a determinationsignal and a transformed original frame signal according to a sequenceparameter; and receiving the transformed original frame signal by aninverse fast Fourier transform (IFFT) circuit to generate the transientoriginal frame signal, and feeding back the transient original framesignal to the channel estimation module to update the channel estimationparameter.
 11. The communication method according to claim 10, whereinthe step of receiving the transformed channel estimation parameter andthe transformed convolution restored frame signal by the secondcomputation circuit of the equalization module to generate the originalframe signal corresponding to the frame signal comprises: receiving thetransformed convolution restored frame signal by a first buffer, andtransforming the transformed convolution restored frame signal to acalculated frame signal by a conjugate calculation circuit; receivingthe transformed channel estimation parameter by a second buffer, andtransforming the transformed channel estimation parameter to acalculated channel estimation parameter by a first permutationcalculation circuit; receiving the transformed equalized frame signal bya third buffer, and transforming the transformed equalized frame signalto a calculated equalized frame signal by a second permutationcalculation circuit; and receiving the transformed original frame signalby a fourth buffer, and transforming the transformed original framesignal to the original frame signal by a third permutation calculationcircuit.
 12. The communication method according to claim 11, wherein thefirst buffer, the second buffer, the third buffer and the fourth bufferfurther receive the determination signal, and output the transformedconvolution restored frame signal, the transformed channel estimationparameter, the transformed equalized frame signal and the transformedoriginal frame signal according to a first-in-first-out (FIFO) sequenceor a last-in-first-out (LIFO) sequence.
 13. The communication methodaccording to claim 9, wherein the step of receiving the channelestimation parameter and the convolution restored frame signal by thefirst computation circuit of the equalization module to generate thetransformed channel estimation parameter and the transformed convolutionrestored frame signal further comprises: receiving the channelestimation parameter and the convolution restored frame signal by aplurality of fast Fourier transform (FFT) circuits to generate thetransformed channel estimation parameter and the transformed convolutionrestored frame signal, wherein both of the transformed channelestimation parameter and the transformed convolution restored framesignal represent a non-spectrum inverted signal; receiving thetransformed channel estimation parameter and the transformed convolutionrestored frame signal by a division circuit to generate the transformedequalized frame signal, wherein the transformed equalized frame signalrepresents a non-spectrum inverted signal; receiving and determiningwhether the transformed equalized frame signal is the spectrum invertedsignal by a grouping circuit, and correspondingly generating atransformed original frame signal; and receiving the transformedoriginal frame signal by an inverse fast Fourier transform (IFFT)circuit to generate the transient original frame signal, and feedingback the transient original frame signal to the channel estimationmodule to update the channel estimation parameter.
 14. The communicationmethod according to claim 13, wherein the FFT circuits further refer toa determination result indicating whether the transformed equalizedframe signal is the spectrum inverted signal to further determine tooutput the transformed channel estimation parameter and the transformedconvolution restored frame signal according to a first-in-first-out(FIFO) sequence or a last-in-first-out (LIFO) sequence.
 15. Thecommunication method according to claim 14, wherein the step ofreceiving the transformed channel estimation parameter and thetransformed convolution restored frame signal by the second computationcircuit of the equalization module to generate the transformed equalizedframe signal to further obtain the original frame signal correspondingto the frame signal further comprises: transforming the transformedconvolution restored frame signal to a calculated frame signal by aconjugate calculation circuit; transforming the transformed channelestimation parameter to a calculated channel estimation parameter by afirst permutation calculation circuit; transforming the transformedequalized frame signal to a calculated equalized frame signal by asecond permutation calculation circuit; and transforming the transformedoriginal frame signal to the original frame signal by a thirdpermutation calculation circuit.
 16. The communication method accordingto claim 9, wherein the frame signal is correspondingly a frame headersignal or a frame body signal; in a first working cycle, when the framesignal that the channel estimation module receives is the header framesignal, the frame header signal is processed by the channel estimationmodule and the equalization module to correspondingly obtain theoriginal frame signal, the equalization module feeds back the originalframe signal to the channel estimation module to update the channelestimation parameter; in a second working cycle following the firstworking cycle, when the frame signal that the channel estimation modulereceives is the frame body signal, the frame body signal is processed bythe channel estimation module and the equalization module tocorrespondingly obtain the original frame signal and is used forcorrecting the situation of the spectrum inverted signal received thatthe communication apparatus receives.